Hydroxyl Group-Enabled Highly Efficient Ligand for Pd-Catalyzed Telomerization of 1,3-Butadiene with CO₂

By introducing hydroxyl group into PPh₃ ligand, a promoter-free palladium catalytic system based on (p-HOC₆H₄)PPh₂ ligand was developed for the telomerization of 1,3-butadiene with CO₂. High activity and selectivity towards CO₂-incorporated divinyl δ-lactone monomer were achieved (TON/TOF: up to 4540/568 h^–1; selectivity of δ-lactone and its isomers: up to 97%). The key role of phenolic hydroxyl group of the ligand in attaining high activity was validated. The good performance of large-scale reaction in batch reactor demonstrated the potential utility of this simple catalytic system in valorizing CO₂ with bulk chemical feedstock.